Isolation and identification of petroleum degrading bacteria from oil contaminated soil & water and assessment of their potentiality in bioremediation

Abstract

Oil spillage has become a global environmental problem. Natural bioremediation is the only eco- friendly solution to resist its devastating environmental and economic damage damage. In this investigation, petroleum tolerant and degrading bacteria were isolated from different oil-contaminated soil and water samples. Bushnell Haas media supplemented with petrol, kerosene, and diesel as sole carbon sources was used for isolation of bacteria capable of degrading these petroleum fractionates. From three soil samples and two water samples, a total of nine bacterial strains were isolated capable of degrading petrol, kerosene and diesel with varying tolerance capacities. The isolates were identified by using standard biochemical tests and morphological studies, and it was determined that these strains belong to six bacterial genera e.g., Staphylococcus, Micrococcus, Streptococcus, Bacillus, Klebsiella and Corynebacterium. The isolated Staphylococcus spp. were found to be the most tolerant isolate withstanding as high as 7% petroleum. The others also exhibit tolerance to varying concentrations of petroleum. All these isolates were able to degrade petroleum completely and produced CO2 within 7 days, with a few exceptions for Bacillus sp. and Klebsiella sp. which required 15 days for complete degradation of kerosene. These isolates seemed to have potential for bioremediation of oil contaminated soil and water. Keywords : Bioremediation, Degradation, Petroleum, Staphylococcus spp., Tolerance